7. Perforation of the TM
n
An example of the audiogram illustrating the flat,
mild, conductive hearing loss that can occur with a
perforated tympanic membrane
9. Middle Ear Disorders
Otitis Media
Most common cause
of transient
conductive hearing
loss in children
Inflamation of the
middle ear
Caused by
eustachian tube
failure
11. Ways to Classify Otitis Media
With or without effusion
Fluid type
Serous
Suppurative
Mucoid
12. Ways to Classify Otitis Media
With or without effusion
Fluid type
Duration
Acute
Chronic
Subacute
Persistent
Recurrent
13. Otitis Media Facts
76-95% of all kids will have one episode of OM by
age 6
Prevalence is highest during the first two years of life
50% of all kids with one episode before their first
birthday will have 6 or more bouts within two years
Most episodes occur in winter and spring
Risk factors
Cleft palate
Down syndrome
Native Americans
Urban poor
Day care
Secondhand smoke
15. Otosclerosis
“a bone disorder that affects the stapes
and the bony labyrinth of the inner ear.
The disease process is characterized
by resorption of bone and new spongy
formation around the stapes and oval
window”
18. Cholesteatoma
“an epithelial pocket that forms on the
tympanic membrane. Once the pocket
forms, the normal shedding of
epithelium results in growth of the
tumor”
26. Noise Induced Hearing Loss
The degree of SNHL depends on
The intensity of the noise
The spectral composition of the noise
The duration of exposure
Individual susceptibility
39. Central Auditory Disorders
VIII Nerve tumors
Other diseases of the VIII Nerve
Neural disorders
Brain Stem disorders
Cochlear neuritis
Diabetes mellitus
Infarcts
Gliomas
Multiple sclerosis
Temporal Lobe disorders
Hinweis der Redaktion
OUTER AND MIDDLE EAR DISORDERS
These pathologies are commonly of two types
-structural defects due to embryologic malformations
-structural changes secondary to infection or trauma
•microtia and atresia--these are the most common congenital malformations of the auricle (pinna) and the external canal.
•Impacted Cerumen--very common cause of temporary conductive HL. Very treatable and preventable. HL that results is flat, conductive, and of varying degree.
•Perforation of the tympanic membrane--These usually occur either by trauma or secondary to OM.
•Other disorders of the outer ear---there are others, but not common and usually don’t affect hearing unless the auditory meatus is blocked
•Otitis Media--the most common cause of transient conductive HL in kids. OM is an inflammation of the middle ear. Caused by eustachian tube malfunction. When it is accompanied by middle ear effusion (fluid) it often causes a conductive HL.
Ways to classify OM:
-OM w/out effusion
-fluid types:
-duration:
76-95% of all kids will have one episode of OM by age 6. Prevalence is highest during the first 2 years, then declines after that. 50% of all kids with one episode before their first birthday will have 6 or more bouts within 2 years. Most episodes occur in winter and spring.
Some populations are more prone to OM--kids with cleft palate or other craniofacial anomalies, Down syndrome, Native Americans, urban poor, day care kids, kids exposed to secondhand smoke.
•Otosclerosis--a bone disorder that affects the stapes and the bony labyrinth of the inner ear. The disease process is characterized by resorption of bone and new spongy formation around the stapes and oval window.
•Cholesteatoma--usually a secondary condition to OM. A cholesteatoma is an epithelial pocket that forms on the tympanic membrane. Once the pocket forms, the normal shedding of epithelium results in growth of the cholesteatoma, or tumor, which is capable of reabsorbing adjacent bone
•Syndromes and inherited Disorders
-syndromic disorders: occurring as part of a constellation of other medical and physical disorders that occur together.
-nonsyndromic disorders: autosomal recessive or dominant genetic conditions in which there is no other significant feature besides HL
•Noise induced HL---very common cause of SNHL in adults. Right up there with presbycusis. This can happen with a one-time exposure to a very loud sound or long-time exposure to constant, softer sounds.
Effects of noise are cumulative. How damaging sounds are to the cochlear are dependent on
-the intensity of the sound.
-the spectral composition of the sound
-duration of exposure
-individual susceptibility
•Other trauma--physical trauma that causes a fracture of the temporal bone and leakage of endolymph.
•Infections--we discussed congenital infections most commonly associated with SNHL that included:
-cytomegalovirus
-HIV
-rubella
-syphilis
-toxoplasmosis
Acquired infections: can be caused by viral or bacterial infections--and by fungi
Some common acquired viral infections that can cause HL
-Herpes Zoster Oticus--caused by a virus that also causes chicken pox.
-Mumps----HL is rare but can occur related to encephalitis.
-syphilis--occurs in the secondary or tertiary stage of the disease.
•Ototoxicity--certain drugs and chemicals are toxic to the cochlea
•Meniere’s Disease--endolymphatic hydrops. Triad of symptoms includes tinnitus, vertigo, and SNHL.
•Presbycusis--decline in thresholds due to aging. The leading contributor to HL in adults. Estimates are that 25-40% of those over 65 have this.
CNS DISORDERS
The nature of the HL that accompanies CANS disorders vary as a function of location of the lesion--more peripheral, more apparent. Disruption in speech perception also gets more subtle as the lesion becomes more central.
•VIII N. Tumors
•Other tumors, cysts, and aneurysms can affect the VIII nerve and the cerebellopontine angle.
•Neural disorders:
-cochlear neuritis--
-diabetes mellitus
•Brain Stem Disorders--these include infarcts, gliomas (fast growing tumors), and multiple sclerosis.
•Temporal-Lobe Disorder